A 50 years old patient who had his kidney transplant 6 months ago visited the hospital with pneumonia like symptoms for 2 months, the infection was similar to tuberculosis. The chest x-ray examination revealed a typical feature of tuberculosis infection. A photochromogenic (orange pigment when exposed to UV light) acid-fast rod bacterium was isolated from the sputum sample. The identified bacteria is:

• A. Mycobacterium avium
• B. Mycobacterium tuberculosis
• C. Mycobacterium kansasii
• D. Mycobacterium leprae